lkml.org 
[lkml]   [2018]   [Jul]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH] tg: count the sum wait time of an task group
On Mon, Jul 02, 2018 at 03:29:39PM +0800, 王贇 wrote:
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 1866e64..ef82ceb 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -862,6 +862,7 @@ static void update_curr_fair(struct rq *rq)
> static inline void
> update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
> {
> + struct task_group *tg;
> struct task_struct *p;
> u64 delta;
>
> @@ -882,6 +883,9 @@ static void update_curr_fair(struct rq *rq)
> return;
> }
> trace_sched_stat_wait(p, delta);
> + } else {
> + tg = group_cfs_rq(se)->tg;
> + __schedstat_add(tg->wait_sum, delta);
> }

You're joking right? This patch is both broken and utterly insane.

You're wanting to update an effectively global variable for every
schedule action (and its broken because it is without any serialization
or atomics).

NAK

\
 
 \ /
  Last update: 2018-07-02 14:05    [W:0.156 / U:4.760 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site